From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78E9FC282DC for ; Wed, 17 Apr 2019 08:02:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 518B22054F for ; Wed, 17 Apr 2019 08:02:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727034AbfDQIC2 (ORCPT ); Wed, 17 Apr 2019 04:02:28 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44824 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726895AbfDQIC2 (ORCPT ); Wed, 17 Apr 2019 04:02:28 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3H7tf2n071022 for ; Wed, 17 Apr 2019 04:02:27 -0400 Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) by mx0a-001b2d01.pphosted.com with ESMTP id 2rwy4t36wy-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 17 Apr 2019 04:02:27 -0400 Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 17 Apr 2019 09:02:21 +0100 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3H82Kue28966936 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Apr 2019 08:02:20 GMT Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3F51F6A04D; Wed, 17 Apr 2019 08:02:20 +0000 (GMT) Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 52F516A054; Wed, 17 Apr 2019 08:02:17 +0000 (GMT) Received: from birb.localdomain (unknown [9.81.203.39]) by b03ledav003.gho.boulder.ibm.com (Postfix) with SMTP; Wed, 17 Apr 2019 08:02:17 +0000 (GMT) Received: by birb.localdomain (Postfix, from userid 1000) id B171A507BC1; Wed, 17 Apr 2019 18:02:13 +1000 (AEST) From: Stewart Smith To: "jianchao.wang" , Bart Van Assche , Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Christoph Hellwig , Ming Lei , Hannes Reinecke , Johannes Thumshirn , James Smart , Dongli Zhang , Laurence Oberman , stable@vger.kernel.org, Joel Stanley Subject: Re: [PATCH] block: Revert v5.0 blk_mq_request_issue_directly() changes In-Reply-To: <300563e5-ebf4-ed62-bbaf-207d3ab5d067@oracle.com> References: <20190404170843.83517-1-bvanassche@acm.org> <87y34jwykf.fsf@linux.vnet.ibm.com> <300563e5-ebf4-ed62-bbaf-207d3ab5d067@oracle.com> Date: Wed, 17 Apr 2019 18:02:13 +1000 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19041708-0004-0000-0000-000014FE8309 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010942; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000284; SDB=6.01190270; UDB=6.00623710; IPR=6.00971068; MB=3.00026479; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-17 08:02:24 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19041708-0005-0000-0000-00008B4A640A Message-Id: <87zhoprrei.fsf@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-17_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904170054 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org "jianchao.wang" writes: > On 4/9/19 1:13 PM, Stewart Smith wrote: >> cpu 0x4a: Vector: 400 (Instruction Access) at [c000203ff398b100] >> pc: c0000000021fe700 >> lr: c0000000002001d8: blk_mq_complete_request+0x34/0x138 > > Would you please figure out what is the source code here with gdb ? > > From the backtrace, it seems not the same issue, because no dm-mpath > is involved here. It turns out it's not the same issue, we just managed to hit it at the same time as the original issue. It's actually a bug in the STRICT_KERNEL_RWX=y code on ppc64le with CONFIG_HUGETLB_PAGE=n that manifests as corrupting random kernel memory and we just happen to hit it in this codepath and only once we brought in "Revert v5.0 blk_mq_request_issue_directly". More details over at https://github.com/linuxppc/issues/issues/237 and there should be a fix for STRICT_KERNEL_RWX coming at some point. -- Stewart Smith OPAL Architect, IBM.